Question

Endoparasites are found inside the host body. Mention the special structure, possessed by these and which enables them to survive in those conditions.

Answer 1

Introduction to parasites

The word parasite was derived from the Greek word ‘parasitos’ which means ‘eating at another's table’. Parasites are the organisms that depend on another organism (host) to fulfil their life processes by harming the host.

Adaptations of endoparasites

Endoparasites live inside the body of the hosts. Some examples include Taenia, Fasciola, Ascaris etc. Adaptations are as follows:


* Presence of suckers and hooks: Taenia and Fasciola possess hooks and suckers.

• Hooks found in Taenia solium are organs of attachment that attach these organisms to the small intestines of the human host.
• Suckers present in Taenia also help in attachment to the alimentary canal of the host.
• In Fasciola, suckers help in adhesion to the host bile duct (mostly sheep) as well as help in ingestion of food.

* Presence of well-developed muscular pharynx: A parasitic roundworm like Ascaris has a well-developed muscular pharynx by which blood, lymph, or fully digested food particles are sucked in or ingested due to the pumping action of the muscular pharynx.

* Loss of the digestive system: A few parasites like tapeworms lack digestive organs because they absorb the digested food of the host, directly through their body surface.

*Presence of thick tegument: Body is externally covered by thick tegument/cuticle which protects parasitic worms from the digestive juices of the host as in the case of Fasciola.

*Production of large amounts of eggs: This increases the chances of survival and ensures efficient maintenance of their life cycle.